Loads of changes and some refactorings

5 files changed, 248 insertions, 273 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 029c90b3..44a28c57 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,6 +28,8 @@ set(SOURCES
 
  CategorizedView.h
  CategorizedView.cpp
+ CategorizedViewCategory.h
+ CategorizedViewCategory.cpp
  CategorizedProxyModel.h
  CategorizedProxyModel.cpp
  InstanceDelegate.h
diff --git a/CategorizedView.cpp b/CategorizedView.cpp
index 6bf18cbc..60230661 100644
--- a/CategorizedView.cpp
+++ b/CategorizedView.cpp
@@ -11,6 +11,8 @@
 #include <QMimeData>
 #include <QScrollBar>
 
+#include "CategorizedViewCategory.h"
+
 template<typename T>
 bool listsIntersect(const QList<T> &l1, const QList<T> t2)
 {
@@ -24,86 +26,6 @@ bool listsIntersect(const QList<T> &l1, const QList<T> t2)
 	return false;
 }
 
-CategorizedView::Category::Category(const QString &text, CategorizedView *view)
-	: view(view), text(text), collapsed(false)
-{
-}
-CategorizedView::Category::Category(const CategorizedView::Category *other) :
-	view(other->view), text(other->text), collapsed(other->collapsed), iconRect(other->iconRect), textRect(other->textRect)
-{
-}
-
-void CategorizedView::Category::drawHeader(QPainter *painter, const int y)
-{
-	painter->save();
-
-	int height = headerHeight() - 4;
-	int collapseSize = height;
-
-	// the icon
-	iconRect = QRect(view->m_rightMargin + 2, 2 + y, collapseSize, collapseSize);
-	painter->setPen(QPen(Qt::black, 1));
-	painter->drawRect(iconRect);
-	static const int margin = 2;
-	QRect iconSubrect = iconRect.adjusted(margin, margin, -margin, -margin);
-	int midX = iconSubrect.center().x();
-	int midY = iconSubrect.center().y();
-	if (collapsed)
-	{
-		painter->drawLine(midX, iconSubrect.top(), midX, iconSubrect.bottom());
-	}
-	painter->drawLine(iconSubrect.left(), midY, iconSubrect.right(), midY);
-
-	// the text
-	int textWidth = painter->fontMetrics().width(text);
-	textRect = QRect(iconRect.right() + 4, y, textWidth, headerHeight());
-	view->style()->drawItemText(painter, textRect, Qt::AlignHCenter | Qt::AlignVCenter, view->palette(), true, text);
-
-	// the line
-	painter->drawLine(textRect.right() + 4, y + headerHeight() / 2, view->contentWidth() - view->m_rightMargin, y + headerHeight() / 2);
-
-	painter->restore();
-}
-
-int CategorizedView::Category::totalHeight() const
-{
-	return headerHeight() + 5 + contentHeight();
-}
-int CategorizedView::Category::headerHeight() const
-{
-	return qApp->fontMetrics().height() + 4;
-}
-int CategorizedView::Category::contentHeight() const
-{
-	if (collapsed)
-	{
-		return 0;
-	}
-	QMap<int, int> rowToHeightMapping;
-	foreach (const QModelIndex &index, view->itemsForCategory(this))
-	{
-		int row = view->categoryInternalPosition(index).second;
-		if (!rowToHeightMapping.contains(row))
-		{
-			rowToHeightMapping.insert(row, view->itemSize(index).height());
-		}
-	}
-	int result = 0;
-	if (!rowToHeightMapping.isEmpty())
-	{
-		for (int i = 0; i < numRows(); ++i)
-		{
-			Q_ASSERT(rowToHeightMapping.contains(i));
-			result += rowToHeightMapping[i];
-		}
-	}
-	return result;
-}
-int CategorizedView::Category::numRows() const
-{
-	return qMax(1, qCeil((qreal)view->numItemsForCategory(this) / (qreal)view->itemsPerRow()));
-}
-
 CategorizedView::CategorizedView(QWidget *parent)
 	: QListView(parent), m_leftMargin(5), m_rightMargin(5), m_bottomMargin(5), m_categoryMargin(5)//, m_updatesDisabled(false), m_categoryEditor(0), m_editedCategory(0)
 {
@@ -115,9 +37,6 @@ CategorizedView::CategorizedView(QWidget *parent)
 	setDragDropMode(QListView::InternalMove);
 	setAcceptDrops(true);
 	setSpacing(10);
-
-	m_cachedCategoryToIndexMapping.setMaxCost(50);
-	m_cachedVisualRects.setMaxCost(50);
 }
 
 CategorizedView::~CategorizedView()
@@ -172,23 +91,21 @@ void CategorizedView::updateGeometries()
 
 	int previousScroll = verticalScrollBar()->value();
 
-	invalidateCaches();
-
-	QMap<QString, Category *> cats;
+	QMap<QString, CategorizedViewCategory *> cats;
 
 	for (int i = 0; i < model()->rowCount(); ++i)
 	{
 		const QString category = model()->index(i, 0).data(CategorizedViewRoles::CategoryRole).toString();
 		if (!cats.contains(category))
 		{
-			Category *old = this->category(category);
+			CategorizedViewCategory *old = this->category(category);
 			if (old)
 			{
-				cats.insert(category, new Category(old));
+				cats.insert(category, new CategorizedViewCategory(old));
 			}
 			else
 			{
-				cats.insert(category, new Category(category, this));
+				cats.insert(category, new CategorizedViewCategory(category, this));
 			}
 		}
 	}
@@ -201,6 +118,11 @@ void CategorizedView::updateGeometries()
 	qDeleteAll(m_categories);
 	m_categories = cats.values();
 
+	for (auto cat : m_categories)
+	{
+		cat->update();
+	}
+
 	if (m_categories.isEmpty())
 	{
 		verticalScrollBar()->setRange(0, 0);
@@ -208,7 +130,7 @@ void CategorizedView::updateGeometries()
 	else
 	{
 		int totalHeight = 0;
-		foreach (const Category *category, m_categories)
+		foreach (const CategorizedViewCategory *category, m_categories)
 		{
 			totalHeight += category->totalHeight() + m_categoryMargin;
 		}
@@ -225,7 +147,7 @@ void CategorizedView::updateGeometries()
 
 bool CategorizedView::isIndexHidden(const QModelIndex &index) const
 {
-	Category *cat = category(index);
+	CategorizedViewCategory *cat = category(index);
 	if (cat)
 	{
 		return cat->collapsed;
@@ -236,11 +158,11 @@ bool CategorizedView::isIndexHidden(const QModelIndex &index) const
 	}
 }
 
-CategorizedView::Category *CategorizedView::category(const QModelIndex &index) const
+CategorizedViewCategory *CategorizedView::category(const QModelIndex &index) const
 {
 	return category(index.data(CategorizedViewRoles::CategoryRole).toString());
 }
-CategorizedView::Category *CategorizedView::category(const QString &cat) const
+CategorizedViewCategory *CategorizedView::category(const QString &cat) const
 {
 	for (int i = 0; i < m_categories.size(); ++i)
 	{
@@ -251,7 +173,7 @@ CategorizedView::Category *CategorizedView::category(const QString &cat) const
 	}
 	return 0;
 }
-CategorizedView::Category *CategorizedView::categoryAt(const QPoint &pos) const
+CategorizedViewCategory *CategorizedView::categoryAt(const QPoint &pos) const
 {
 	for (int i = 0; i < m_categories.size(); ++i)
 	{
@@ -263,70 +185,6 @@ CategorizedView::Category *CategorizedView::categoryAt(const QPoint &pos) const
 	return 0;
 }
 
-int CategorizedView::numItemsForCategory(const CategorizedView::Category *category) const
-{
-	return itemsForCategory(category).size();
-}
-QList<QModelIndex> CategorizedView::itemsForCategory(const CategorizedView::Category *category) const
-{
-	if (!m_cachedCategoryToIndexMapping.contains(category) || true)
-	{
-		QList<QModelIndex> *indices = new QList<QModelIndex>();
-		for (int i = 0; i < model()->rowCount(); ++i)
-		{
-			if (model()->index(i, 0).data(CategorizedViewRoles::CategoryRole).toString() == category->text)
-			{
-				indices->append(model()->index(i, 0));
-			}
-		}
-		m_cachedCategoryToIndexMapping.insert(category, indices, indices->size());
-	}
-	return *m_cachedCategoryToIndexMapping.object(category);
-}
-QModelIndex CategorizedView::firstItemForCategory(const CategorizedView::Category *category) const
-{
-	QList<QModelIndex> indices = itemsForCategory(category);
-	QModelIndex first;
-	foreach (const QModelIndex &index, indices)
-	{
-		if (index.row() < first.row() || !first.isValid())
-		{
-			first = index;
-		}
-	}
-
-	return first;
-}
-QModelIndex CategorizedView::lastItemForCategory(const CategorizedView::Category *category) const
-{
-	QList<QModelIndex> indices = itemsForCategory(category);
-	QModelIndex last;
-	foreach (const QModelIndex &index, indices)
-	{
-		if (index.row() > last.row() || !last.isValid())
-		{
-			last = index;
-		}
-	}
-
-	return last;
-}
-
-int CategorizedView::categoryTop(const CategorizedView::Category *category) const
-{
-	int res = 0;
-	const QList<Category *> cats = sortedCategories();
-	for (int i = 0; i < cats.size(); ++i)
-	{
-		if (cats.at(i) == category)
-		{
-			break;
-		}
-		res += cats.at(i)->totalHeight() + m_categoryMargin;
-	}
-	return res;
-}
-
 int CategorizedView::itemsPerRow() const
 {
 	return qFloor((qreal)(contentWidth()) / (qreal)(itemWidth() + spacing()));
@@ -336,49 +194,34 @@ int CategorizedView::contentWidth() const
 	return width() - m_leftMargin - m_rightMargin;
 }
 
-QList<CategorizedView::Category *> CategorizedView::sortedCategories() const
-{
-	QList<Category *> out = m_categories;
-	qSort(out.begin(), out.end(), [](const Category *c1, const Category *c2) { return c1->text < c2->text; });
-	return out;
-}
-
 int CategorizedView::itemWidth() const
 {
-	if (m_cachedItemWidth == -1)
-	{
-		m_cachedItemWidth = itemDelegate()->sizeHint(viewOptions(), model()->index(model()->rowCount() -1, 0)).width();
-	}
-	return m_cachedItemWidth;
+	return itemDelegate()->sizeHint(viewOptions(), model()->index(model()->rowCount() -1, 0)).width();
 }
 
-QSize CategorizedView::itemSize(const QModelIndex &index) const
+int CategorizedView::categoryRowHeight(const QModelIndex &index) const
 {
-	if (!m_cachedItemSizes.contains(index))
+	QModelIndexList indices;
+	int internalRow = categoryInternalPosition(index).second;
+	foreach (const QModelIndex &i, category(index)->items())
 	{
-		QModelIndexList indices;
-		int internalRow = categoryInternalPosition(index).second;
-		foreach (const QModelIndex &i, itemsForCategory(category(index)))
+		if (categoryInternalPosition(i).second == internalRow)
 		{
-			if (categoryInternalPosition(i).second == internalRow)
-			{
-				indices.append(i);
-			}
+			indices.append(i);
 		}
+	}
 
-		int largestHeight = 0;
-		foreach (const QModelIndex &i, indices)
-		{
-			largestHeight = qMax(largestHeight, itemDelegate()->sizeHint(viewOptions(), i).height());
-		}
-		m_cachedItemSizes.insert(index, new QSize(itemWidth(), largestHeight));
+	int largestHeight = 0;
+	foreach (const QModelIndex &i, indices)
+	{
+		largestHeight = qMax(largestHeight, itemDelegate()->sizeHint(viewOptions(), i).height());
 	}
-	return *m_cachedItemSizes.object(index);
+	return largestHeight;
 }
 
 QPair<int, int> CategorizedView::categoryInternalPosition(const QModelIndex &index) const
 {
-	QList<QModelIndex> indices = itemsForCategory(category(index));
+	QList<QModelIndex> indices = category(index)->items();
 	int x = 0;
 	int y = 0;
 	const int perRow = itemsPerRow();
@@ -397,14 +240,25 @@ QPair<int, int> CategorizedView::categoryInternalPosition(const QModelIndex &ind
 	}
 	return qMakePair(x, y);
 }
-int CategorizedView::itemHeightForCategoryRow(const CategorizedView::Category *category, const int internalRow) const
+int CategorizedView::categoryInternalRowTop(const QModelIndex &index) const
 {
-	foreach (const QModelIndex &i, itemsForCategory(category))
+	CategorizedViewCategory *cat = category(index);
+	int categoryInternalRow = categoryInternalPosition(index).second;
+	int result = 0;
+	for (int i = 0; i < categoryInternalRow; ++i)
+	{
+		result += cat->rowHeights.at(i);
+	}
+	return result;
+}
+int CategorizedView::itemHeightForCategoryRow(const CategorizedViewCategory *category, const int internalRow) const
+{
+	foreach (const QModelIndex &i, category->items())
 	{
 		QPair<int, int> pos = categoryInternalPosition(i);
 		if (pos.second == internalRow)
 		{
-			return itemSize(i).height();
+			return categoryRowHeight(i);
 		}
 	}
 	return -1;
@@ -586,13 +440,10 @@ void CategorizedView::paintEvent(QPaintEvent *event)
 	QPainter painter(this->viewport());
 	painter.translate(-offset());
 
-	// FIXME we shouldn't need to do this
-	invalidateCaches();
-
 	int y = 0;
 	for (int i = 0; i < m_categories.size(); ++i)
 	{
-		Category *category = m_categories.at(i);
+		CategorizedViewCategory *category = m_categories.at(i);
 		category->drawHeader(&painter, y);
 		y += category->totalHeight() + m_categoryMargin;
 	}
@@ -627,16 +478,16 @@ void CategorizedView::paintEvent(QPaintEvent *event)
 
 	if (!m_lastDragPosition.isNull())
 	{
-		QPair<Category *, int> pair = rowDropPos(m_lastDragPosition);
-		Category *category = pair.first;
+		QPair<CategorizedViewCategory *, int> pair = rowDropPos(m_lastDragPosition);
+		CategorizedViewCategory *category = pair.first;
 		int row = pair.second;
 		if (category)
 		{
-			int internalRow = row - firstItemForCategory(category).row();
+			int internalRow = row - category->firstRow;
 			QLine line;
-			if (internalRow >= numItemsForCategory(category))
+			if (internalRow >= category->numItems())
 			{
-				QRect toTheRightOfRect = visualRect(lastItemForCategory(category));
+				QRect toTheRightOfRect = visualRect(category->lastItem());
 				line = QLine(toTheRightOfRect.topRight(), toTheRightOfRect.bottomRight());
 			}
 			else
@@ -700,8 +551,8 @@ void CategorizedView::dropEvent(QDropEvent *event)
 		return;
 	}
 
-	QPair<Category *, int> dropPos = rowDropPos(event->pos() + offset());
-	const Category *category = dropPos.first;
+	QPair<CategorizedViewCategory *, int> dropPos = rowDropPos(event->pos() + offset());
+	const CategorizedViewCategory *category = dropPos.first;
 	const int row = dropPos.second;
 
 	if (row == -1)
@@ -772,24 +623,17 @@ QRect CategorizedView::visualRect(const QModelIndex &index) const
 		return QRect();
 	}
 
-	if (!m_cachedVisualRects.contains(index))
-	{
-		const Category *cat = category(index);
-		QPair<int, int> pos = categoryInternalPosition(index);
-		int x = pos.first;
-		int y = pos.second;
-
-		QSize size = itemSize(index);
+	const CategorizedViewCategory *cat = category(index);
+	QPair<int, int> pos = categoryInternalPosition(index);
+	int x = pos.first;
+	int y = pos.second;
 
-		QRect *out = new QRect;
-		out->setTop(categoryTop(cat) + cat->headerHeight() + 5 + y * size.height());
-		out->setLeft(spacing() + x * itemWidth() + x * spacing());
-		out->setSize(size);
+	QRect out;
+	out.setTop(cat->top() + cat->headerHeight() + 5 + categoryInternalRowTop(index));
+	out.setLeft(spacing() + x * itemWidth() + x * spacing());
+	out.setSize(itemDelegate()->sizeHint(viewOptions(), index));
 
-		m_cachedVisualRects.insert(index, out);
-	}
-
-	return *m_cachedVisualRects.object(index);
+	return out;
 }
 /*
 void CategorizedView::startCategoryEditor(Category *category)
@@ -908,13 +752,13 @@ bool CategorizedView::isDragEventAccepted(QDropEvent *event)
 	}
 	return true;
 }
-QPair<CategorizedView::Category *, int> CategorizedView::rowDropPos(const QPoint &pos)
+QPair<CategorizedViewCategory *, int> CategorizedView::rowDropPos(const QPoint &pos)
 {
 	// check that we aren't on a category header and calculate which category we're in
-	Category *category = 0;
+	CategorizedViewCategory *category = 0;
 	{
 		int y = 0;
-		foreach (Category *cat, m_categories)
+		foreach (CategorizedViewCategory *cat, m_categories)
 		{
 			if (pos.y() > y && pos.y() < (y + cat->headerHeight()))
 			{
@@ -933,7 +777,7 @@ QPair<CategorizedView::Category *, int> CategorizedView::rowDropPos(const QPoint
 		}
 	}
 
-	QList<QModelIndex> indices = itemsForCategory(category);
+	QList<QModelIndex> indices = category->items();
 
 	// calculate the internal column
 	int internalColumn = -1;
@@ -967,7 +811,7 @@ QPair<CategorizedView::Category *, int> CategorizedView::rowDropPos(const QPoint
 	int internalRow = -1;
 	{
 		// FIXME rework the drag and drop code
-		const int top = categoryTop(category);
+		const int top = category->top();
 		for (int r = 0, h = top; r < category->numRows(); h += itemHeightForCategoryRow(category, r), ++r)
 		{
 			if (pos.y() > h && pos.y() < (h + itemHeightForCategoryRow(category, r)))
@@ -1000,14 +844,6 @@ QPair<CategorizedView::Category *, int> CategorizedView::rowDropPos(const QPoint
 	return qMakePair(category, indices.at(categoryRow).row());
 }
 
-void CategorizedView::invalidateCaches()
-{
-	m_cachedItemWidth = -1;
-	m_cachedCategoryToIndexMapping.clear();
-	m_cachedVisualRects.clear();
-	m_cachedItemSizes.clear();
-}
-
 QPoint CategorizedView::offset() const
 {
 	return QPoint(horizontalOffset(), verticalOffset());
diff --git a/CategorizedView.h b/CategorizedView.h
index 08d43be8..0550c7f8 100644
--- a/CategorizedView.h
+++ b/CategorizedView.h
@@ -3,7 +3,6 @@
 
 #include <QListView>
 #include <QLineEdit>
-#include <QCache>
 
 struct CategorizedViewRoles
 {
@@ -15,6 +14,8 @@ struct CategorizedViewRoles
 	};
 };
 
+struct CategorizedViewCategory;
+
 class CategorizedView : public QListView
 {
 	Q_OBJECT
@@ -28,7 +29,7 @@ public:
 	void setSelection(const QRect &rect, const QItemSelectionModel::SelectionFlags commands) override;
 
 protected slots:
-	 void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles);
+	void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles);
 	virtual void rowsInserted(const QModelIndex &parent, int start, int end);
 	virtual void rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end);
 	virtual void updateGeometries();
@@ -50,57 +51,27 @@ protected:
 	void startDrag(Qt::DropActions supportedActions) override;
 
 private:
-	struct Category
-	{
-		Category(const QString &text, CategorizedView *view);
-		Category(const Category *other);
-		CategorizedView *view;
-		QString text;
-		bool collapsed;
-		QRect iconRect;
-		QRect textRect;
-
-		void drawHeader(QPainter *painter, const int y);
-		int totalHeight() const;
-		int headerHeight() const;
-		int contentHeight() const;
-		int numRows() const;
-	};
-	friend struct Category;
+	friend struct CategorizedViewCategory;
 
-	QList<Category *> m_categories;
-	mutable QCache<const Category *, QList<QModelIndex> > m_cachedCategoryToIndexMapping;
-	mutable QCache<const QModelIndex, QRect> m_cachedVisualRects;
+	QList<CategorizedViewCategory *> m_categories;
 
 	int m_leftMargin;
 	int m_rightMargin;
 	int m_bottomMargin;
 	int m_categoryMargin;
-	int m_itemSpacing;
 
 	//bool m_updatesDisabled;
 
-	Category *category(const QModelIndex &index) const;
-	Category *category(const QString &cat) const;
-	Category *categoryAt(const QPoint &pos) const;
-	int numItemsForCategory(const Category *category) const;
-	QList<QModelIndex> itemsForCategory(const Category *category) const;
-	QModelIndex firstItemForCategory(const Category *category) const;
-	QModelIndex lastItemForCategory(const Category *category) const;
-
-	int categoryTop(const Category *category) const;
+	CategorizedViewCategory *category(const QModelIndex &index) const;
+	CategorizedViewCategory *category(const QString &cat) const;
+	CategorizedViewCategory *categoryAt(const QPoint &pos) const;
 
 	int itemsPerRow() const;
 	int contentWidth() const;
 
-	static bool lessThanCategoryPointer(const Category *c1, const Category *c2);
-	QList<Category *> sortedCategories() const;
-
 private:
-	mutable int m_cachedItemWidth;
-	mutable QCache<QModelIndex, QSize> m_cachedItemSizes;
 	int itemWidth() const;
-	QSize itemSize(const QModelIndex &index) const;
+	int categoryRowHeight(const QModelIndex &index) const;
 
 	/*QLineEdit *m_categoryEditor;
 	Category *m_editedCategory;
@@ -113,21 +84,20 @@ private:
 	QPoint m_pressedPosition;
 	QPersistentModelIndex m_pressedIndex;
 	bool m_pressedAlreadySelected;
-	Category *m_pressedCategory;
+	CategorizedViewCategory *m_pressedCategory;
 	QItemSelectionModel::SelectionFlag m_ctrlDragSelectionFlag;
 	QPoint m_lastDragPosition;
 
 	QPair<int, int> categoryInternalPosition(const QModelIndex &index) const;
-	int itemHeightForCategoryRow(const Category *category, const int internalRow) const;
+	int categoryInternalRowTop(const QModelIndex &index) const;
+	int itemHeightForCategoryRow(const CategorizedViewCategory *category, const int internalRow) const;
 
 	QPixmap renderToPixmap(const QModelIndexList &indices, QRect *r) const;
 	QList<QPair<QRect, QModelIndex> > draggablePaintPairs(const QModelIndexList &indices, QRect *r) const;
 
 	bool isDragEventAccepted(QDropEvent *event);
 
-	QPair<Category *, int> rowDropPos(const QPoint &pos);
-
-	void invalidateCaches();
+	QPair<CategorizedViewCategory *, int> rowDropPos(const QPoint &pos);
 
 	QPoint offset() const;
 };
diff --git a/CategorizedViewCategory.cpp b/CategorizedViewCategory.cpp
new file mode 100644
index 00000000..b82ffc96
--- /dev/null
+++ b/CategorizedViewCategory.cpp
@@ -0,0 +1,128 @@
+#include "CategorizedViewCategory.h"
+
+#include <QModelIndex>
+#include <QPainter>
+#include <QtMath>
+
+#include "CategorizedView.h"
+
+CategorizedViewCategory::CategorizedViewCategory(const QString &text, CategorizedView *view)
+	: view(view), text(text), collapsed(false)
+{
+}
+CategorizedViewCategory::CategorizedViewCategory(const CategorizedViewCategory *other) :
+	view(other->view), text(other->text), collapsed(other->collapsed), iconRect(other->iconRect), textRect(other->textRect)
+{
+}
+
+void CategorizedViewCategory::update()
+{
+	firstRow = firstItem().row();
+
+	rowHeights = QVector<int>(numRows());
+	for (int i = 0; i < numRows(); ++i)
+	{
+		rowHeights[i] = view->categoryRowHeight(view->model()->index(i * view->itemsPerRow() + firstRow, 0));
+	}
+}
+
+void CategorizedViewCategory::drawHeader(QPainter *painter, const int y)
+{
+	painter->save();
+
+	int height = headerHeight() - 4;
+	int collapseSize = height;
+
+	// the icon
+	iconRect = QRect(view->m_rightMargin + 2, 2 + y, collapseSize, collapseSize);
+	painter->setPen(QPen(Qt::black, 1));
+	painter->drawRect(iconRect);
+	static const int margin = 2;
+	QRect iconSubrect = iconRect.adjusted(margin, margin, -margin, -margin);
+	int midX = iconSubrect.center().x();
+	int midY = iconSubrect.center().y();
+	if (collapsed)
+	{
+		painter->drawLine(midX, iconSubrect.top(), midX, iconSubrect.bottom());
+	}
+	painter->drawLine(iconSubrect.left(), midY, iconSubrect.right(), midY);
+
+	// the text
+	int textWidth = painter->fontMetrics().width(text);
+	textRect = QRect(iconRect.right() + 4, y, textWidth, headerHeight());
+	painter->setBrush(view->viewOptions().palette.text());
+	view->style()->drawItemText(painter, textRect, Qt::AlignHCenter | Qt::AlignVCenter, view->viewport()->palette(), true, text);
+
+	// the line
+	painter->drawLine(textRect.right() + 4, y + headerHeight() / 2, view->contentWidth() - view->m_rightMargin, y + headerHeight() / 2);
+
+	painter->restore();
+}
+
+int CategorizedViewCategory::totalHeight() const
+{
+	return headerHeight() + 5 + contentHeight();
+}
+int CategorizedViewCategory::headerHeight() const
+{
+	return view->viewport()->fontMetrics().height() + 4;
+}
+int CategorizedViewCategory::contentHeight() const
+{
+	if (collapsed)
+	{
+		return 0;
+	}
+	int result = 0;
+	for (int i = 0; i < rowHeights.size(); ++i)
+	{
+		result += rowHeights[i];
+	}
+	return result;
+}
+int CategorizedViewCategory::numRows() const
+{
+	return qMax(1, qCeil((qreal)numItems() / (qreal)view->itemsPerRow()));
+}
+int CategorizedViewCategory::top() const
+{
+	int res = 0;
+	const QList<CategorizedViewCategory *> cats = view->m_categories;
+	for (int i = 0; i < cats.size(); ++i)
+	{
+		if (cats.at(i) == this)
+		{
+			break;
+		}
+		res += cats.at(i)->totalHeight() + view->m_categoryMargin;
+	}
+	return res;
+}
+
+QList<QModelIndex> CategorizedViewCategory::items() const
+{
+	QList<QModelIndex> indices;
+	for (int i = 0; i < view->model()->rowCount(); ++i)
+	{
+		const QModelIndex index = view->model()->index(i, 0);
+		if (index.data(CategorizedViewRoles::CategoryRole).toString() == text)
+		{
+			indices.append(index);
+		}
+	}
+	return indices;
+}
+int CategorizedViewCategory::numItems() const
+{
+	return items().size();
+}
+QModelIndex CategorizedViewCategory::firstItem() const
+{
+	QList<QModelIndex> indices = items();
+	return indices.isEmpty() ? QModelIndex() : indices.first();
+}
+QModelIndex CategorizedViewCategory::lastItem() const
+{
+	QList<QModelIndex> indices = items();
+	return indices.isEmpty() ? QModelIndex() : indices.last();
+}
diff --git a/CategorizedViewCategory.h b/CategorizedViewCategory.h
new file mode 100644
index 00000000..cb6ef8c5
--- /dev/null
+++ b/CategorizedViewCategory.h
@@ -0,0 +1,39 @@
+#ifndef CATEGORIZEDVIEWROW_H
+#define CATEGORIZEDVIEWROW_H
+
+#include <QString>
+#include <QRect>
+#include <QVector>
+
+class CategorizedView;
+class QPainter;
+class QModelIndex;
+
+struct CategorizedViewCategory
+{
+	CategorizedViewCategory(const QString &text, CategorizedView *view);
+	CategorizedViewCategory(const CategorizedViewCategory *other);
+	CategorizedView *view;
+	QString text;
+	bool collapsed;
+	QRect iconRect;
+	QRect textRect;
+	QVector<int> rowHeights;
+	int firstRow;
+
+	void update();
+
+	void drawHeader(QPainter *painter, const int y);
+	int totalHeight() const;
+	int headerHeight() const;
+	int contentHeight() const;
+	int numRows() const;
+	int top() const;
+
+	QList<QModelIndex> items() const;
+	int numItems() const;
+	QModelIndex firstItem() const;
+	QModelIndex lastItem() const;
+};
+
+#endif // CATEGORIZEDVIEWROW_H